Most of the infiltration attempts by Russian, Chinese and Iranian agents were halted by Microsoft security software and the targets notified, he said.
The Biden campaign did not confirm the attempt, although it said in a statement that it was aware of the Microsoft report.
“We are a large target, so it is not surprising to see malicious activity directed at the campaign or our staff," Trump campaign deputy press secretary Thea McDonald said.
In June, Google disclosed that Hurricane Panda had targeted Trump campaign staffers while Iranian hackers had attempted to breach accounts of Biden campaign workers.
By contrast, Brookie said, “it’s pretty evident that the Russian attempts (Microsoft disclosed) were focused on electoral processes and groups working on that.”—-AP Technology Writer Matt O’Brien contributed to this report from Providence, Rhode Island.